The Truth Behind Opportunity's Last Message and It's Final Days On Mars
"My Batteries are low, and it's getting dark" - those words struck a chord with people around the world, but of course the truth is the actual last transmissions from Opportunity and how it ended its mission on Mars are less poetic, but worthy of discussion. So let's discuss the technology behind the rover, the workarounds and hacks that kept it running and the actions of the team in charge of the mission.

Boberg XR9S & XR45S: The Bullpup Pistols
Rock Island is selling these two Boberg pistols as part of a Lot 1089 in their upcoming Regional auction on February 14th, 2019.

Arne Boberg founded Boberg Arms in 2009 and released his first pistol in 2011, the XR9-S. This was followed by the longer XR9-L, and then the XR-45S in 2014. The conceit of the Boberg pistol is basically that of the Bullpup rifle: maximizing barrel length while minimizing overall length. To this end, Boberg used an unconventional system of pulling cartridges out the back of the magazine rather than pushing them forward, allowing about an inch of extra barrel in a given pistol. The resulting feed system is a bit complex and very cool, and reminiscent of the old British Mars pistols. It is not without its faults, though, and the lowest priced Boberg pistols were over $1000 retail, which significantly limited their sales in a concealed carry market awash with good options at half the price. In 2016 Boberg sold the gun to the Bond Arms company, which markets is today as the Bond Bullpup. Original Boberg production guns have, thus, become collectible items for those interested in unusual handguns.

What If You Detonated a Nuclear Bomb In The Marianas Trench? (Science not Fantasy)
Did you ever wonder what happened if you detonated a nuclear bomb in the Marianas Trench? No? We neither! Let us find out together!

The Earth and Moon are like identical twins, made up of the exact same materials -- which is really strange, since no other celestial bodies we know of share this kind of chemical relationship. What's responsible for this special connection? Looking for an answer, planetary scientist and MacArthur "Genius" Sarah T. Stewart discovered a new kind of astronomical object -- a synestia -- and a new way to solve the mystery of the Moon's origin.

This is not what an atom really looks like | Michelle Thaller
Artistic depictions of the atom have deceived us all.

- Though artistic renderings suggest otherwise, electrons do not, in fact, move around a nucleus the same way the planets move around a star — at all.

- Electrons also are not tiny balls, they're more wavelike. Also, in regard to their location, a single electron can also be an entire sphere around the nucleus of an atom.

- As for their movement, electrons do have a spin, but they're not actually spinning. They're not actually moving around. You can think of them as clouds that exist in different locations around the nucleus based on how much energy they have.

Reactor Online. Sensors Online. Weapons Online. All Systems Nominal! In this Special Edition of War Stories, Russ Bullock (President, Piranha Games), Derek James (Designer), and Brian Windover (Lead Engineer) discuss the development of the upcoming MechWarrior 5: Mercenaries. We also speak with Jordan Weisman, founder of FASA Corporation and creator of the BattleTech universe, and get a little bit of a history of the MechWarrior and BattleTech franchises.

Never Run Out Of Ammo | Magazine Pez Dispenser | Tactical Rifleman
First, you have to admit, these puppies are pretty awesome. Having a “Speed Reload” pouch that refills itself is a great idea. Why have a 30rd belt in your machinegun, when you can have a 300rd belt in your machinegun?

Now there are pros & cons with these tactics, just like everything else. However, the magnetic box that held 10 magazines, just really impressed the hell out of me. Second, I deliberately ran these mags with only one or two rounds in them, otherwise the video would have been 3 hours long, and cost $4k in ammo. The internal springs of these Ammoback dispensers are calibrated for full weight magazines. So, you might have seen a couple hiccups in the video. When I was beating on these things, the three months prior to filming, they ran flawlessly with full mags.
If you are active military, running gun trucks or PSD, you should REALLY look at investing my taxpayers’ money in outfitting your trucks with these boxes.
If you are Law Enforcement, and run a Patrol Rifle in the trunk of your cruiser, you should really look at the model with the shoulder straps. Throw it over your head and grab your rifle... and you are responding with 6 mags love that any gang banger will back down from. SWAT? Yep, there should be no more loose magazines floating around the bread truck; they should all be stored away to AmmoBack dispensers.
If you are a civilian, these products may open doors for you in unique ways. Competitive shooters can save space on 3-gun belts, freeing up space for my shotgun shells. Our “tactical” minded followers and easily find ways to apply this technology to magazine storage.
Still skeptical? So was I. However, the more you play with these “Pez Dispensers” the more they actually make sense for certain situations. No, I’m not going to replace all the mags on my kit with this; but that 10-mag box is sitting loaded in my suburban and students will keep seeing these at my classes.

Interesting... I see the advantages for competitive shooters. Might be beneficial for units like SWAT teams who have short-duration deployments and don’t have to lug 50 lbs of field gear on their back as well. Reliability might also be a concern in the field, although that would likely improve with time.

It certainly does look like a handy way to keep a set of loaded magazines on hand for emergencies....

From experience, I've discovered having the right tool at the right place within easy reach is invaluable; not having had the pleasure of experiencing life and death situations in combat, I would guess having easily accessible ammunition refills, besides a working rifle, should compare.

Special Ops Emergency Ammo Resupply | Tactical Rifleman
I was out at the rifle range, working with some Air Force Medical people, and they had brought about a dozen crates of good military 5.56mm ammo. Each crate has two ammo cans. Each ammo can, when opened, provides you with a number of cloth bandoliers. Each bandolier has 4 cardboard sleeves, a speed loader, and a black safety pin. Each cardboard sleeve contains 30rds of ammo on three 10rd stripper clips (for use with the speed loader). That makes for a lot of trash when you’re doing 4 hours of Failure and Box Drills out on the hot range.
What prompted me to do this video was when some of the Air Force guys were saying that they had no idea what the bandoliers or the safety pin was for. It was all just trash to them. I started having flashbacks to my time in different military schools and times when seasoned soldiers took the time to explain it to Private Erickson. So, let’s share a little military history, or at least, this is how it was explained to me. You’ll know why I grab the bandoliers and safety pins at the range now, when no one else will; and you’ll never look at those ammo bandoliers the same again.

The Advanced Combat Rifle (ACR) was a United States Army program, started in 1986, to find a replacement for the M16 assault rifle. Under the stress of battle the average soldier with an M16 may shoot a target at 45 meters, but hit probability is reduced to one out of ten shots on target by 220 meters. Because of this, the ACR program was initiated in the late 1980s to create a weapon that could double the hit probability.[1] The ACR program was preceded by older programs such as the Special Purpose Individual Weapon. The program ended in 1990 after an expenditure of approximately US$300 million.

Phase I of the program started in February 1986 when development contracts were placed with six companies: AAI Corporation, Ares Incorporated, Colt's Manufacturing Company, Heckler & Koch (H&K), McDonnell Douglas Helicopter Systems (MDHS), and Steyr Mannlicher.
Two weapons were cut from the list before Phase II started. The companies started an appeals process and were eventually re-instated, but too late to see testing before the ACR program ended.
Eugene Stoner’s Ares Incorporated also entered their Advanced Individual Weapon System (AIWS), which used a 5mm tracer round, but had to withdraw due to ongoing problems. The AIWS shared some features with the Steyr entry, notably the "rising chamber" action and "telescoped" cartridge.
McDonnell Douglas Helicopter Systems, originally Hughes Helicopters, planned to enter their design using a plastic-cased cartridge they called a chiclet due to its box-like profile. Their first loads used duplex or triplex loads of normal projectiles, but the recoil was too high, so these were replaced with fléchettes, first with five of them in a 11-millimetre (.42 in) round, eventually three in a 8.6-millimetre (.338 in) round.

Phase III[edit]

Main article: AAI ACR
AAI Corporation entered the latest variant of their long line of experimental fléchette rifles. Their entry used a standard 5.56×45mm cartridge case firing a 1.6×41.27mm fléchette of 0.66 grams at 1402 m/s. One of the biggest complaints about their earlier efforts was the loud muzzle blast, a problem that is hard to avoid with a sabotted round. As a result, AAI added a flash hider/sound suppressor that reduced the muzzle blast to just louder than an M16A2. While the standard 5.56×45mm case was used, the rifle was not safe to fire using standard ammunition due to the design of the gas system. A special magazine was used to prevent soldiers loading standard 5.56×45mm NATO ammunition into the magazine, but rounds could still be chambered by hand. The weapon was limited to three-round bursts despite the fact that one of the main reasons for using a fléchette is its low recoil. This particular design was less complex than some of their earlier models, which could switch between fléchette ammunition for rapid fire and standard 5.56 NATO rounds for long-range semi-automatic fire.
H&K[edit]
Main article: Heckler & Koch G11
The Heckler & Koch G11 series used caseless ammunition where the propellant was molded onto the bullet itself, making the round smaller and much lighter. The new K2 version used in the ACR tests held 45 rounds in a single long magazine lying along the top of the barrel, leading to a distinctive and somewhat blocky appearance.
Steyr[edit]
Main article: Steyr ACR
The last entry submitted was the Steyr ACR, another fléchette-firing weapon. The Steyr differed from the AAI in the details of the round, which used a plastic shell casing to reduce weight. The firing mechanism was quite complex as a result, moving the entire chamber as opposed to just the bolt. When fired, the chamber would move down where a new round would be pushed in from the rear, forcing the spent cartridge case forward out of the chamber where it would drop out through an ejection port behind the pistol grip. The chamber would then move back into firing position on a spring, where it would lock in front of a fixed breechblock. On firing, the sabot traveled down the barrel with the fléchette and was quickly "stripped" off upon exit. This was found to present a hazard in combat, where the sabots could hit other soldiers or bounce off the ground when being fired prone. Like the AAI weapon, the Steyr was limited to three round bursts.
Colt[edit]

Colt ACR/M16A2E2
Main article: Colt ACR
One of the more traditional of the ACR prototypes was the Colt ACR, which was a highly modified version of the existing M16A2. Modifications were the addition of a new optical sighting system, a hydraulic buffer to smooth out recoil during automatic fire, and a collapsing butt stock similar to the one already in use on the carbine versions of the M16. The key design change was the use of "duplex rounds", a single cartridge with two smaller bullets in it. Olin Corporation produced three different rounds for testing, the first consisting of two tungsten projectiles in a long-necked case, the second used a standard-length case with two 1.7 grams (27 gr), 4.0-millimetre (0.158 in) tungsten projectiles, and the final entry was another standard-length case with two 5.7-millimetre (0.224 in) projectiles, one 2.3 grams (35 gr), the other 2.1 g (33 gr). The latter was eventually selected for submission to the ACR trials. The basic idea of the duplex load is to increase the number of projectiles fired, which is the primary determinant of battlefield casualties.[2] However, they significantly reduced accuracy, requiring the user to also carry traditional ammunition for long-range shots.

Outcome[edit]
Although all the designs worked well, none managed to meet or even approach the 100% improvement over the M16A2 that the program demanded. In 1986/7, the United States Army Infantry School had published a report asserting that the rifle, as a weapon, had already reached its peak, and the only way to really improve matters was to use an exploding warhead[citation needed]. This led to the ending of the ACR program in April 1990, and led the way to the Objective Individual Combat Weapon program. The program's total cost was approximately US$300 million.[3]

Three kilogrammes seem ideal for anyone to use it, especially with the recoil compensation to compensate for the likely increased velocity of the intermediate round and the lower weight of the barrel and rifle.

I've already thought of tracer ammunition to track it on automatic fire, but thought it's also likely to give away your position.

Most of them have the potential, since an increased rate of fire would group a three round burst pretty close together; fletchettes by their nature have a low recoil.

Full automatic is multiple targets and/or suppressive fire, at least at the smallarms level, and I think six hundred metres is about the extent the unaided Mark One Eyeball can accurately target anything.

Modern customized assault carbines, which I will presume special forces can afford and order, are rather accurate to their designed range, though I'm thinking of rifles conceived and manufactured two to three decades after these trials.

With full automatic, you probably would want to use a bipod or sling, or a vehicle pintle mount; at close quarters it's sort of a last resort, since you won't care if the barrel overheats, which I think might not be the case with the accelerator rifle.

If you need a telescope for full automatic fire, you probably have the latitude to stabilize the rifle before you pull the trigger.

There's also a two or three technological level gap between the current standard issue assault rifle, and the default Traveller Advanced Combat Rifle, and my take on it, at least for the Solomani, would be using different barrel lengths for different roles, and an especially heavy amd long one for full automatic fire for team and squad support.

The only improvements seem fifty percent longer range, with a smaller cartridge and lighter materials, but the same damage potential.

There's also a two or three technological level gap between the current standard issue assault rifle, and the default Traveller Advanced Combat Rifle, and my take on it, at least for the Solomani, would be using different barrel lengths for different roles, and an especially heavy amd long one for full automatic fire for team and squad support.

Didn’t Stoner have a weapon system like that years ago? I have vague memories of it so maybe it wasn’t very successful.